Testing device for hollow articles



Sept. 17, 1957 w. J. STECKER TESTINGOEVIOE: FOR HOLLOW ARTOLEs 2 Sheets-Sheet l Filed NOV. 26, 1952 f ma# m W ,JW w M@ F m L u W,

Sept. 17, 1957 W J. STECKER 2,806,371

TESTING DEVICE FOR HOLLOW ARTICLES Filed Nov. 2e. 1952 2 sheets-sheet 2 FIGB, 22

United States Patent l TESTING DEVICE FOR HOLLOW ARTICLES Walter Julius Stecker, Pagedale, Mo., assignor to Wagner Electric Corporation, St. Louis, Mo., a corporation of Delaware Application November 26, 1952, Serial No. 322,691 4 Claims. (Cl. 73-49.2)

This invention relates to improvements in devices for testing hollow articles, cast bodies and the like, and more particularly to a testing device having pressure sensitive indicator means for testing sealed articles, castings and the like for leaks.

It is well known that the sealing means for hollow articles under fluid pressure must be considerably more certain where the fluid is a gas than where the luid is a liquid. Heretofore, testing .devices for sealed hollow articles have made use of the liquid submergence method in which a leak may be detected by bubbles appearing on the surface of the liquid. This is .a particularly messy testing procedure and is not suitable to high speed production requirements. It is particularly unsuited for the testing of hollow articles of cast construction where it is necessary or desirable to test the casting for porosity defects. yIn other cases, the liquid submergence method cannot be used at all.

.It is an object of the present invention to provide a device forpressure testing sealed hollow articles, casting and the like which is exceedingly sensitive in its response to leakage in the article being tested.

Another object of the present invention is to provide a device for pressure testing `the internal spaces of hollow articles which is adapted to high speed production :and is positive in its indication of the presence yof leaks.

It is -another object of this invention to provide a device for testing hollow articles -which utilizes a gaseous fluid under controlled differential pressure `conditions to therelby increase the scope of its usefulness and avoid the.

objections to liquid submergence testing devices.

The present invention consists in a testing device having a test article receiving chamber which can be sealed at known or preferably at substantially atmospheric pressure and means for introducing fluid under pressure to the interior of the article `to .be tested, the article being rst place-d in the sealed chamber. The internal pressure creates a difference of pressures between the interior of the article and the chamber surrounding the article which may be easily watched by means of a manometer to detect the presence of leaks. Since the only source of pressure tuid for the chamber is the interior of the article being tested, any leakage out of the article increases the pressure in the surrounding space of the chamber .and changes the height of the liquid column in the manometer so that a positive indication can be made of the presence or absence of leaks in the article.

The invention further consists in the parts and combina tion of parts hereinafter to be described in connection with the accompanying drawings, wherein:

Fig. l is `a front elevational View of the device for testing hollow articles; p

Fig. 2 is a side elevational view of the device;

Fig. 3 is a sectional elevational view of the article testing 'device as .seen at line 3 3 in Fig. l

Fig. 4 is a section-alplan view of the testing device showing an article in position to be tested, the view being lieke-n at line 4-4 in Fig. `1 fand Fig. 5 is a view similar to Fig. 4 wherein the device and the larticle therein are shown in test position.

=First referring to Figs. 1, 2 and 3, a preferred embodiment of the present invention includes :a container 10 having the interior chamber 11 which is open at the upper face 12. The container 10 has a front wall 13 opposite side walls 14 and 15 and a rear wall 16 provided with an extension 17. The upper face 12 of the container is provided with a channel or groove 18 to receive a sealing strip 19 of any suitable cross sectional shape. In the sample shown, the seal 19 is circular in cross section. A cover 20 lits over the open face 12 of the container 10 and rests upon the sealing means 19 so that the chamber 11 can be fully sealed.

The testing -device is adapted for relatively high speed production testing of hollow articles as compared with immersion testing methods. To this end, cover 20 is connected to a supporting plate 21 by means of a plurality of studs 22 slidable in suitable apertures in the plate 21. Each of the studs 22 is provided with a removable head 23 for retaining a pressure spring 24 about the stud 22'and `against the plate 21. Plate 21 is fixed to the projecting arm 25 of a cover bracket 26. The bracket 26 is pivoted on a suitable pivot stud 27 which is iixed in the projection 17 of t-he rear wall 16 of the container 10. A pair of jam nuts 28 engage the upper end of the pivot stud 27 to hold the bracket 26 i-n proper position for pivoting movement in a plane above the face 12 of the container. One edge of the cover 20 is provided with a stop plate 29 for the purpose of locating the cover in position over the face 12 and against the sealing means 19.

lThe cover 20 is normally held in its elevated position against the supporting plate 21 by means of springs 24 pushing against the stud heads 23. In the raised position of the cover, t-he -bracket 26 may be pivoted. to one side to swing the cover .away from the opening of the chamber 11. This greatly facilitates and speeds up the operation .of placing articles in the chamber 11 or of removing them. Means for holding the cover 2i) in closed position *over chamber 11 consists of a cam 30 mounted on pivot pin 31 in the bifurcated end 32 of the arm 25. Cam 30 is provided with a suitable boss 33 to receive a lever 34 for operating the cam 30 from the ful-l l-ine position shown in Fig. 2, wherein `cover 20 is held closed, to the dotted line position shown thereof.

The interior of chamber 11 is provided with suitable ribs 36 projecting inwardly from the front wall 13 and cooperating ribs 37 projecting inwardly from the opposite, rear wall 16. These ribs 36 and 37 are suitably formed to receive the article A which is to be tested. In the present embodiment, the device is shown to be adapted for testing the wheel cylinders of automotive brake systems. It is understood, however, that this invention is not to be limited to articles of this type. The wheel cylinder has been selected for purposes.` of describing one article which is suitable for this testing device. A wheel cylinder body is generally formed with a boss 111 at one side provided with a threaded port 112 to which the usual hydraulic supply line is connected. The cylinder 110 contains a pair of oppositely positioned plungers 113 and 114 movable toward and away from a central position adjacent the port 112. These plungers are sealed at the inner side thereof by sealing cups 116 and respectively, with the aid of a relatively weak spring 117 located between the cups 115 and 116 for urging the plungers 113 and 114 outwardly in the cylinarticle A is placed in chamber 11 with the `body 11G i 3 a resting in suitable cutoutsin ribs 37 and with boss 111 restingbetween' ribs'361 In order to be able to supply fluid under pressure to the interior of article A, a coupling device 39 is located inthe .wall `131.' ofi container 10`l so asi-tolregister with`the inlet port 112. Flh'isdeviceconsistsirra sleevenftllslidL ably.l mounted; in aportV 4=11 in lwa'll- 1B" and sealed therein by: meansu ofi thepacking ring-42am thefthr'ea'ded `gland 43s! Theiinner endlofl sleeve' 40lisiprovid`ed1witha 'suitable sealing ring` 44whichl engagesithe bosslllll off article AA closely about the'- inlet port1L12 thereof. The outer' 'end'y ofsleeve 40has= althread'ed port-45 'to which isconnected a conduit 46 (Fig: 2) leading4 to asource ('not-lshownl offuid under.' pressure.`r` Means rfor4 reciprocating sleeve'V tainer? Lever 47 is providediwithl complementary-v members having oiset portions 50 (Fig.` 1) which' pass on'lopposite: sides' of the'sleeve 4t]Xy and engage projections S11-formed! on' said sleeve.' Each of the-offset portions' 50' oflfthe lever 477 has-anape'rtureSZ- which leosely Yreceives the' projections 51, thatis in the direction-:at substantiallyright an'glesto the axisl ofv pin 513, in= order to allow for the arcuate travel of the lever 47T relative tothestraight linetravell ofi sleeve 40.

Meansl for indicating the pressure condition withinv charn'berll comprises a manometer, Fig. 1'. The man# bring sealing means tlon the inner end of the sleeve L" around port 112' to-mal e a pressure tight connection;

A suitable `control valve (not shown) is then opened in the pressure fluid supply line 46 from the source of Huid under pressure to supply the uid internally of the cylinder 110; Plungers lll-Bland 114 are, thereby, caused to move apart' to the position shown in Fig. 5 and the'cups 11f5 andll'eare pressed into sealing engagement'with` the interiorv wall of the cylinder 110; The cover 20 is next swung from itsV open position to af position above the* face lf2 of the container it) as determined by the stop plate 29 engaging wall 151 The cam operating handle 34-may then be moved in a direction to cause cam' 30 to bearV upon and press the cover Ztl downwardly against the sealing means 19 in opposition to the cover lifting springs 24.

When the cover is located in its closed'position, as described, the attendant notes the initial height of the manometer fluid in column 57 and watches for the requiredl test period to determine if there is a change in the height- If a change occurs inthe height of the column inA leg 57,' that is if the level L drops, it indicates the presence of a leak from the'interior of the cylinder 110 to the interior of the container chamber 11. Such a leak causes an increase in the pressure in chamber 11 and a displacement;v of the air in the chamber toward the manometer leg 57. At the completion'of the test, the controlj vaive supplying llui'dlunder pressure through the sleeve 40 is first closed. Thereafter, the cover 2'0` for the container 10 may be openedv by reversing the procedure above described. Following this, the lever 47 may be operated to move the sleeve itaway from the article A so that the article may be quickly removed from the'conta'iner. It is Vnecessary to follow this sequence of operations in order to avoid' releasing the` uid under pressure into the chamber 11 before the cover 20 is released. This protects the manometer against damage duez to` high' pressure release:y

In order to achieve the maximum sensitivity from the present device, the unoccupied volume of chamber 11 or the volume which is external of the article A being tested should be held to a minimum. If the present device is constructed for testing articles` having the same shape, it is quite easy to construct vthe container 10 with a minimum chamber volume. Onthe'. other band,ifthe=device is to be used for testing afnumber of diierentshaped ar.` ticles, the volume of chamber A11; may` be. conveniently varied in order to achieve a minimum volume relation:- ship, by the use of non-resilient filler pieces. Such ller pieces areindi'cated atF in Figs.- -4and 5. Itisalsopossible to achieve ameasure o sensitivity by applying a manometer tube having a bore which is small but not small enough to create an artificial level due to capillary attraction. y

The. presenti testin'g2deviee fulfillsl the foregoing in'- numerated` other objects o-'fi thel presenti invention :and`

constitutes an'VV improvement over' priory testingy devices'in that it makes. use ofiA a comparisoncff` pressure -valu'esbef tween the interior of an article to be tested andf'theexfteriorl space? inwbich the article is enclosed and sealed; It is= unde'rstood` that the foregoing description of'L a` pre-v fer-red :embodiment is not t'oef be taken asl limiting-the scope"of the'repres'ent invention?. exceptas itYV may be;- so

required? intheappended claims:

Whatisclatned is:

l?. Alidevicev` for testing' for leaks' in hollow articles having at leastton'e movable pressurel displaced means therein and aV pressure" fluid inlet port' comprisingla' chamberedA container'f'or the hollow Yarticles to" be tested,l couplinglmeans'extending through ay 'wall of saidchanr-V ber andimevable into'sealedr test pressure communication with the article in said chamber at the inletport, said; coupling mea-nsconnecting" the interior of the', hollow testE article with an external' source of testA fluid under pressure', cover means sealing the chamber at substan tially ambient pressure conditions with the hollow'te'st article therein; and pressure sensitiveV means connected with-the cliarnber'to respond to pressure changes in the chamber surrounding the hollow 'test article! and' indicate leaks in sucharticle.

2. A'devicefor testing for leaks in` hollow articles having internally' movable pressure responsiveA means anda pressure iluid'inlet port' comprising a chamberedy container for thehollow article to be tested', a removable. member. sealing the chamber from ambient pressure conditions to stabilize th'epressure external to the hollow test, article andl within" the chamber, lever operated means connected. with said sealingy member for removing the lat-ter to open.

the chamber for. removing and inserting hollow test arti.-l

cles, testpressure coupling means connectingy asource of'- test'uidunder pressurewith the inlet port for the interior of the hollow test' articles, said coupling liavingav sliding.

seal insaid container for quick make and' break. connection with the articles to bel tested, another seal on said coupling' engaging the" inlet port of the. test` article,.and: a man'orneter'co'nnected with'the chamber externally ofthe. hollow test articles to indicate pressure in the chamber.

3'. A device for testing. for leaks in a series of hollow articles having a pressure uid inlet port, acontainer having an open sidedl chamber sized'to receivethearticles,

a cover for the open side of. said chamber, a pivoted arm carrying said cover and movable to permit rapid opening and closing of the chamber, a coupling. connectedA with; a source of test luidA under pressure. and slidably. movable through a stationary container wall into and. out. of sealed connection with the inlet port. for eachy article to he tested, lever means connected with. said coupling to move the same rapidly intoand out of connection with. the

inlet port for the articles, and a. manometer connected.v Y

into the chamber to indicate pressure in said container external to the articles being tested. A

4. A device for testing for leaks in hollow articles having internally located pressure sealing means slidable in the hollow article and pressure fluid inlet means, comprising a container having a chamber with a minimum volume im relation to the external size of the articles to be tested, cover means hermetically closing the chamber with a test article therein, movable coupling means connecting a source of test gas under pressure through the inlet means with the interior of the test article, sealing means in a Wall of the chamber surrounding said coupling means and sealing the same during movement thereof, a sealing element on said coupling means surrounding the inlet means for the test article to seal against leaks around the article between said coupling means and the chamber external to the test article, and pressure sensing and indicating means connected into the chamber for response to pressure increases in the chamber due to leaks in the test article.

References Cited in the le of this patent UNITED STATES PATENTS 

